HID: picolcd: sanity check report size in raw_event() callback

commit 844817e47eef14141cf59b8d5ac08dd11c0a9189 upstream.

The report passed to us from transport driver could potentially be
arbitrarily large, therefore we better sanity-check it so that raw_data
that we hold in picolcd_pending structure are always kept within proper
bounds.

Reported-by: Steven Vittitoe <scvitti@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/hid/hid-picolcd.c b/drivers/hid/hid-picolcd.c
index 1daeaca..c952131 100644 (file)
--- a/drivers/hid/hid-picolcd.c
+++ b/drivers/hid/hid-picolcd.c
@@ -2382,6 +2382,12 @@ static int picolcd_raw_event(struct hid_device *hdev,
        if (!data)
                return 1;
 
+       if (size > 64) {
+               hid_warn(hdev, "invalid size value (%d) for picolcd raw event\n",
+                               size);
+               return 0;
+       }
+
        if (report->id == REPORT_KEY_STATE) {
                if (data->input_keys)
                        ret = picolcd_raw_keypad(data, report, raw_data+1, size-1);